Segmental grinding wheel



Feb. 17. 19.25.

H. W. H. BETH SEGMENTAL GRINDLNG WHEEL Filed Jan. 7 1924 Um. W. H. Befh.

Patented Feb. 1-7, 1925.

.. UNII'IIED STATES-PATENT OFFICE.

'inUG w. H. BETH, or 'wOnCESTEn, MASSACHUSETTS, Assronbn. To 'NORTON Conn PANY, or WORCESTER, MASSACHUSETTS, A CORPORATION or MASSACHUSETTS.

SEGMENTAL GRINDING WHEEL.

Application filed January 7, 1924. Serial 1T0. 684,776.

To all whomit may concern:

Be it known that I, HUGO W. H. BETH, a citizen of the United States of America, residing at Worcester, in the county of Worcester, and State of Massachusetts, have invented certain new and useful Improvements in Segmental Grinding Wheels, of which the following is a full, clear, and exact specification.

My invention relates to the art of abrading and more particularly to a grinding wheel made up of abrasive segments supported in a chuck to form an annular, plane grinding surface.

One type of grinding wheel, known as a ring wheel, comprises a metal chuck which has abrasive segments held between an outer annular ring or flange and inner clamping or wedging blocks. Heretofore, each segmenthas been made with an outer curved surface. intended to fit snugly against the inner wall of the flange of the chuck, and an inner surface which is engaged throughout its extent by the adjustable wedging block.

3 Since the abrasive'segments are frequently warped durin manufacture. they may not fitproperly between the flange and the clamping blocks, so that they will be subjected to uneven strains when wedged in place and consequently broken. Even if not broken when initially assembled, these fragile blocks may later break during the grinding operation when the wheel is mo-' mentarily required to take a deep cut. Such breakage may mean a considerable loss to the user, hence eyery effort has been madeto make the curved surfaces of the abrasive segments correct in shape, but due to difficulties inherent. in the processes of menufl facture, it has not been found possible to do .80 at all times.

It is accordingly an object of my invention to provide a ring wheel construction which overcomes these difficulties and parv ticularly to so shape the abrasive segments and cooperating parts of the chuck that the forces caused by the clamping action will be transmitted directly through the segment opposite such lands.

. Fig.1 is a fragmentary front elevation of a chuck carrying my abrasive segments;

Fig. 2 is a fragmentary sectional. view taken approximately on line 22 of Fig. 1 showing howthe segments are fastened in place; and

Fig. 3 is a perspective view of one of my segmental blocks. l

In accordance with my invention, I propose to so form each segmental block; of

abrasive that compressional forces set up by clamping the block in the chuck will be transmitted directly ,through the block and n will not break it. -To this end,I propose to form lands on the segmental block which 7 are spaced apart and will engage the inner periphery of the chuck ring, and I so form the parts that the wedging block may con-4 tact only with portions of the abrasive seg- A chuck of the general type employed in connection with this invention, as illustrated in the drawings, comprises a wheel or plate 10, substantially disk shaped, which has a suitable hub' 11 arranged for mount- 30 ing the disk on a spindle, all of which may be constructed as. is well known in the art. To the outer portion of the plate 10 s fixed by means of screws 12 a ring 13 WlllOll 1s so shaped as to carry the abraslve segments. 35 This ring 13 is preferably formed with outer and inner flanges 14 and 15 projecting therefrom. The abrasive blocks are held in 13081-- tion against'the inner periphery of the outer flange .14 by means of a setof clamping 9 blocks 16.

Frusto-conical members 17 engaging par tial conical surfaces on the blocks 16 and the inner flange 15 are provided to wedge the blocks 16 in place. These wedg ng 05 members 17 are adjuistably held 111 position outer faces 24 being by means of studs 18 which are screwthreaded into the annular ring 13 and are locked againstrotation by means of locking screws 19. The outer end of each stud 18 is threaded and provided with a nut 20,

the under face of which engages a countersunk portion of the member 17 As the nut is turned, the frusto-conical member 17 will be forced inwardly to wedge the block 16 against the abrasive segment 22 and clamp the latter against the annular flange 14. The central opening in each member 17 is slightly larger than the stud18 to permlt the former to shift slightly as the nut 20 is tightened.

The abrasive segments 22, which are so arranged in the chuck as to grind on their radial faces 23', are preferably formed substantially in the shape shown in Fig; 3, the preferably curved to y to the inner periph- The surface conform substantial eral surface of the flange 14.

'24 is held out of contactvwith such flange by means of lands 25 and 26 formed as raised ridges on the "abrasive blocks. The tops of the lands are preferably given a cylindrical curvature of such a radius as to fit the inner surface of the flange 14 so that the lands will contact therewith throughout an extensive area.

A similar set of lands or projections 27 and 28 are preferably formed on the other side of the segment directly opposite the lands 25 and 26, so that the clamping blocks 16 may contact therewith only in areas opposite those which contact with the flange 14, whereby any force applied to clamp the segment in place will be transmitted in a direct line through the segment. If desired, the clamping block 16 may be cut away centrally and provided with lands 29 and 30 which will contact with the abrasive segment only opposite the lands 25 and 26, it being understood that whether the lands are on the abrasive segments or on the blocks is immaterial so far as this invention is concerned. As illustrated, I have shownboth the blocks and the abrasive segments provided with lands, but only one set is ordinarily intended to be used. The segments are otherwise so shaped that they will form a substantially continuous ring when assembled, which presents a plane face for grinding. If desired the segments may be spaced apart to form separate abrading teeth.

The manner of assembling and using this wheel will be apparent from the above disclosure. When the segments have become worn, a ring 30 of a suitable height may be inserted to raise them sufliciently above the adjacent faces of the flange and clamping members. In order to replace one or all of the segments, it is merely necessary to loosen the wedging members 1 It will, therefore, be seen that in accordance with this invention I so construct and arrange the parts of the wheel that the wedging pressure transm1tted from the frusto-conical member 17 through the block 16 directly to the outer set of lands and to the annular flange 14 cannot crack or break the .block, as might happen if the pressure were applied opposite an unsupported portion of the segment. There is no pressure against the segment throughout its middle portion and therefore no forces are applied which can break the block medially. Hence, it is immaterial whether the blocks are accurately made and whether the flanges and clamping blocks are accurately positioned, since the forces which hold the abrasive segments in place are properly localized to care for the necessary stresses set up in the ring type of wheel by clamping the abrasive segments in place.

A ring wheel of this type has many distinct advantages over solid wheels of cylindrical shape, among which may be mentioned economy and efficiency. There is more usable abrasive in the segments than in a solid wheel and the segments can be manufactured at a lower cost than a solid wheel of the same size. If a segment is accidentally broken it may be easily and cheaply replaced, whereas solid wheel, if broken, must be discarded. B so constructing such a wheel as to prevent serious losses due to breakage, I have made it feasible to use the ring wheel to a greater extent and more efficiently than heretofore.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An abrasive segment having a plane grinding face and opposed sides adapted to be clamped in a chuck, one of said opposed sides having spaced projecting lands arranged to contact with an adjacent chuck surface.

2. An abrasive segment for use in a chuck, having a plane grinding surface and opposed sides adapted to he clamped in a chuck, one side having a set of lands projecting above the main surface thereof and the other side having a further set of projecting lands opposite to those first named, whereby the lands only will contact with opposed clamping portions of the chuck.

3. A grinding wheel comprising a disk having an annular flange thereon, a plurality of lane faced abrasive segments having promoting lands which alone contact with the flange and means including adjustable blocks to clamp said segments against the fiange,-said parts being so constructed and arranged that the blocks contact with the segments only opposite sai'd lands.

at. A grinding wheel comprising a disk having an annular flange thereon, a set of alone contact with the clamping block whereabrasive segments having projecting lands by a compressional force will be transmitted contacting with the periphery of the flange directly and normally from the clamping and means including an adiustable clamping block through the segment to the flange.

8 block to wedge each segment against the Si ed at Worcester, Massachusetts, this flange, each of said segments having lands 3rd ay of J an., 1924. opposite those engaging the flange which HUGO W. H. BET 

